# try/80_database/20_redis_key_migrator_unit_try.rb

require_relative '../../support/test_helpers'

## Test basic Redis migration with mock data (without OT dependencies)
require 'redis'
require 'uri'

OT.boot! :test, true

# Setup section - get Redis config from OT.conf
redis_uri = URI.parse(OT.conf['redis']['uri'])
@redis_host = redis_uri.host
@redis_port = redis_uri.port

class SimpleRedisKeyMigrator
  attr_reader :source_uri, :target_uri, :options, :statistics

  DEFAULT_OPTIONS = {
    batch_size: 100,
    scan_count: 1000,
    timeout: 5000,
    copy_mode: true,
    retry_attempts: 3,
    progress_interval: 100
  }.freeze

  def initialize(source_uri, target_uri, options = {})
    @source_uri = source_uri.is_a?(String) ? URI.parse(source_uri) : source_uri
    @target_uri = target_uri.is_a?(String) ? URI.parse(target_uri) : target_uri
    @options = DEFAULT_OPTIONS.merge(options)
    @statistics = initialize_statistics
  end

  def migrate_keys(pattern = '*', &progress_block)
    validate_migration_params
    strategy = determine_migration_strategy
    keys = discover_keys(pattern)
    return @statistics if keys.empty?

    case strategy
    when :copy
      migrate_using_copy_command(keys, &progress_block)
    when :migrate
      migrate_using_migrate_command(keys, &progress_block)
    when :dump_restore
      migrate_using_dump_restore(keys, &progress_block)
    end

    @statistics
  end

  private

  def initialize_statistics
    {
      total_keys: 0,
      migrated_keys: 0,
      failed_keys: 0,
      start_time: nil,
      end_time: nil,
      strategy_used: nil,
      errors: []
    }
  end

  def validate_migration_params
    raise ArgumentError, "Source URI cannot be nil" unless @source_uri
    raise ArgumentError, "Target URI cannot be nil" unless @target_uri
    raise ArgumentError, "Source and target cannot be identical" if uris_identical?
  end

  def uris_identical?
    source_normalized = normalize_uri(@source_uri)
    target_normalized = normalize_uri(@target_uri)
    source_normalized == target_normalized
  end

  def normalize_uri(uri)
    "#{uri.host}:#{uri.port}/#{uri.path&.gsub('/', '') || 0}"
  end

  def determine_migration_strategy
    if same_redis_instance?
      @statistics[:strategy_used] = :copy
      :copy
    else
      @statistics[:strategy_used] = :dump_restore
      :dump_restore
    end
  end

  def same_redis_instance?
    @source_uri.host == @target_uri.host &&
    @source_uri.port == @target_uri.port &&
    @source_uri.user == @target_uri.user &&
    @source_uri.password == @target_uri.password
  end

  def discover_keys(pattern)
    source_client = create_redis_client(@source_uri)
    @statistics[:start_time] = Time.now
    keys = source_client.keys(pattern)  # Simple implementation for test
    @statistics[:total_keys] = keys.size
    keys
  ensure
    source_client&.disconnect!
  end

  def migrate_using_copy_command(keys, &progress_block)
    # Mock implementation for testing - simulate COPY command
    @statistics[:migrated_keys] = keys.size
    @statistics[:end_time] = Time.now
  end

  def migrate_using_migrate_command(keys, &progress_block)
    # Mock implementation for testing
    @statistics[:migrated_keys] = keys.size
    @statistics[:end_time] = Time.now
  end

  def migrate_using_dump_restore(keys, &progress_block)
    # Mock implementation for testing
    @statistics[:migrated_keys] = keys.size
    @statistics[:end_time] = Time.now
  end

  def create_redis_client(uri)
    db_number = if uri.path && !uri.path.empty? && uri.path != '/'
                  uri.path.gsub('/', '').to_i
                else
                  0
                end

    Redis.new(
      host: uri.host,
      port: uri.port || @redis_port,
      db: db_number,
      password: uri.password,
      username: uri.user,
      timeout: 30,
      reconnect_attempts: 3
    )
  end
end

## Test basic initialization
source_uri = "redis://#{@redis_host}:#{@redis_port}/14"
target_uri = "redis://#{@redis_host}:#{@redis_port}/15"

migrator = SimpleRedisKeyMigrator.new(source_uri, target_uri)
migrator.class.name.split('::').last
#=> "SimpleRedisKeyMigrator"

## Test strategy detection for same instance
source_uri = "redis://#{@redis_host}:#{@redis_port}/14"
target_uri = "redis://#{@redis_host}:#{@redis_port}/15"

migrator = SimpleRedisKeyMigrator.new(source_uri, target_uri)
strategy = migrator.send(:determine_migration_strategy)
strategy
#=> :copy

## Test strategy detection for different instances
source_uri = "redis://#{@redis_host}:#{@redis_port}/14"
target_uri = "redis://otherhost:#{@redis_port}/15"

migrator = SimpleRedisKeyMigrator.new(source_uri, target_uri)
strategy = migrator.send(:determine_migration_strategy)
strategy
#=> :dump_restore

## Test error handling for nil source
begin
  migrator = SimpleRedisKeyMigrator.new(nil, "redis://#{@redis_host}:#{@redis_port}/15")
  migrator.migrate_keys('*')
  false
rescue ArgumentError => e
  e.message.include?("Source URI cannot be nil")
end
#=> true

## Test error handling for identical URIs
begin
  same_uri = "redis://#{@redis_host}:#{@redis_port}/14"
  migrator = SimpleRedisKeyMigrator.new(same_uri, same_uri)
  migrator.migrate_keys('*')
  false
rescue ArgumentError => e
  e.message.include?("Source and target cannot be identical")
end
#=> true

## Test basic migration with test data
test_db_source = 14

# Setup test data
source_client = Redis.new(host: @redis_host, port: @redis_port, db: test_db_source)
source_client.flushdb
source_client.set('test:key1', 'value1')
source_client.set('test:key2', 'value2')

source_uri = "redis://#{@redis_host}:#{@redis_port}/#{test_db_source}"
target_uri = "redis://#{@redis_host}:#{@redis_port}/15"

migrator = SimpleRedisKeyMigrator.new(source_uri, target_uri)
stats = migrator.migrate_keys('test:*')

source_client.disconnect!

[stats[:total_keys], stats[:migrated_keys], stats[:strategy_used]]
#=> [2, 2, :copy]

## Cleanup
source_client = Redis.new(host: @redis_host, port: @redis_port, db: 14)
source_client.flushdb
source_client.disconnect!

true
